Stop device for machine tools



Dec. 6, 1949 M. J. KARR 2,490,307

STOP DEVICE FOR MACHINE TOOLS Filed Aug. 18, 1947 INVENTOR. Ma /4a J05PHA??? BYWW Patented Dec. 6, 1949 STOP DEVICE FOR MACHINE TOOLS MichaelJoseph Karr, Kalamazoo, Mich assignor to Atlas Press Company, Kalamazoo,Mich., a

corporation of Michigan Application August 18, 1947, Serial No. 769,265

1 Claim.

This invention relates to adjustable stop devices for machine tools, andmore particularly to a quick-setting stop for a drill press or the like.

The invention provides a micro-adjustable stop device for positivelystopping the travel of the working element of a machine tool, such as adrill in a drill press, at any desired predetermined position, and alsoprovides for adlusting the stop device quickly and rapidly to differentstop positions for different depths to which it is desired to machinethe work material. The invention also includes mechanism for insuringagainst accidental movement of the stop device.

In general, the invention comprises a microadjustable, quick-settingstop member which is movably mounted on a stud and is adapted to bepositioned thereon at various heights above a cooperating abutment stopsupported on a stationary portion of the machine, the stud beingconnected to the reciprocatory member of the machine, such as to thequill of a drill press.

In the accompanying drawing illustrating one embodiment of theinvention, Fig. 1 is a perspective view of the support table and workinghead portions of a drill press equipped with the new stop device;

Fig. 2 is an enlarged perspective view of the upper portion of the studand the stop member shown in Fig." 1;

Fig. 3 is a top plan view of the stop member as shown in Figs. 1 and 2;and

Fig. 4 is an enlarged detailed view of the support lever for themicro-adjusting worm screw.

eferring to the drawings, the drill press I includes an adjustable worksupporting table 2 and a drill head 3 in which a reciprocable quill 4 isslideably mounted. The drill spindle, provided with a collar 5, isjournaled in quill 4 and carries a chuck at its lower end, within whicha drill 5 is held. The work material 1 to be drilled is supported ontable 2 and is disposed in the proper position beneath drill 6. Thedrill spindle is driven through the usual gearing, which is locatedwithin the drill head, and vertical reciprocation of quill 4 and drill 6is controlled by handles 8 which are connected to a hub 9 fixed to theend of a shaft ill mounted on and extending from the frame of the drillhead. The front portion of hub 9 and one of the handles 8 have beenbroken away in Fig. 1 in order to show fully the construction andarrangement of the top device. Rotary motion imparted to shaft ID bymanual rotation of handles 8 is transferred to quill 4 through the usualrack and pinion or other equivalent mechanism.

A clamp Support H is secured to quill 4 and serves as a mount for a baror stud I2, the lower end of which is secured to the clamp by a bolt12'. Stud 13 xtends upwardly from clamp H and parallel with quill 4,passing through a slot provided in a rib projection 13 which extendsfrom the frame of the drill head and which serves as the abutment stop.One face of the stud is pr vided with regul rly spa ed thread teeth H,the purpose Of which will be explained later. It is apparent that thebar or stud l2. being connected to quill 4 and being disp sed in.parallel relation thereto, moves equally with the quill as it isreciprocated toward or away from the work material.

Referring particularly to Figs. 2 and a stop member it which isslideably mounted on stud 12, comprises a .U-shaped shell or frame IS,the top and bottom faces of which are each provided with an aligned holethrough which stud I2 extends. The dimensions of these holes are :suchas to permit the shell to move freely longitudinally relative to thestud but with out permitting lateral play of the stud therein. An L-shaped lever H, shown in Figs. 2-4, is pivotally mounted by a pin i8between the top and bot-- tom faces of frame 16 and the central portionof one of the angularly disposed lever arms I1 is cut away toaccommodate a worm screw 19 therein, the latter being rotatably mounted.on a pin 20 which extends between the top and bottom faces of thislever arm.

The threads of the worm screw are cooperatively engaged with the teeth Mon stud l2, thereby locking the stop member to the stud or bar, and byrotating screw 49, stop member l5 may he traversed longitudinally of thebar. A spring 2! such as a coil spring is mounted around pivot pin [8with one end pressing against the other lever arm I1" and with the otherend acting against a pin 22 which extends between the top and bottomfaces of frame I6. Due to the tension of spring 2|, lever I1 is normallyheld in a position to force worm screw l9 firmly against the toothedface of stud l i, thereby assuring positive engagement of the screw withthe thread teeth and thus providing for support and retention of thestop member I5 on the stud at any desired position above the abutmentstop !3. The strength of spring 2| is sufiicient to prevent accidentalrotation of screw I9 and to prevent accidental displacement of the stopmember on the stud.

By virtue of the provision and cooperative arrangement of lever I1 andspring 2I, the stop member may be rapidly set or reset at any desiredposition on stud I2 by manually depressing the lever arm II" against thepressure of spring 2I, thus pivoting the lever in a clockwise directionas viewed in the drawings and disengaging screw I9 from teeth I4,thereby permitting the stop member to be moved manually and freelyrelative to the length of stud I2 and independently of screw I9. Forfine adjustment of the stop member on the stud, worm screw I9 is used,the peripheral portions of the threads thereof being knurled or serratedto provide good finger purchase thereon. To facilitate adjustment withscrew I9 lever arm I'I" may be depressed slightly against the pressureof spring 2I to relieve somewhat the pressure with which the screw isheld against the stud.

The size and shape of frame I6 are such that the bottom face thereofcomes into stopping engagement with the upper face of rib I3 as stud I2moves downwardly with quill 4, and the strength of spring 2I issufficient to prevent displacement of the stop member under thiscondition.

A pointer 25 is swingably mounted on the top face of frame I6 and isdisposed to cooperate with a graduated scale 26, which is secured to theframe of the drill head, to indicate the height of the bottom face ofstop member I5 above the top of the rib or abutment stop I3, and hencealso thereby to indicate the permitted downward travel of the quill 4and drill' 6.

a -As shown-in Fig. 4, a reference mark 21 is provided on the outer edgeof the top face of lever arm I1, and the upper surface of the top threadof worm I9 is marked with radial graduations 28 which are an evenmultiple of the number of thread teeth per unit of length on stud II.For example, if 10 teeth per inch are provided on the stud, and if thetop thread of worm I 9 is marked with 10 equally spaced radialgraduations, the rotation of the worm from one radial graduation mark tothe next with respect to reference mark 21 raises or lowers the stopmember on the stud 5 of an inch, and hence the depth of the travel ofdrill 6 may be varied accordingly.

In operation, the work material I is locked or otherwise positioned onthe support table 2 and the table is then adjusted to bring the workmaterial within the range of travel of the drill, which is thencontacted with the work material. The stop member I is lowered to engagethe abutment stop I3 and the reading on the scale 26 indicated bypointer 25 is taken. The quicksetting lever I1 is depressed so as todisengage the worm screw from the stud and so that stop member I5 can beraised manually above the abutment stop I3 to a height approximatelyequal to the depth to which it is desired to drill the work material,and final adjustment of the stop member to the exact height desired iseffected by rotation of screw I9. The reference mark 21 and radialgraduations 28 may be utilized to eifect micro-adjustment of the stopmember on the stud. Thereafter, the drill press may be operated to drillthe work material and the engagement of the under face of stop member I5with the upper surface of abutment stop I3 positively preventsover-travel of the drill in the work.

In the foregoin description, I have referred to the application of theinvention to a drill press and particularly as employed for eifectingpositive and automatic stopping of the drill press quill when it hastravelled the desired distance toward the work material. However, theinvention is equally applicable to other machine tools and may beadapted advantageously as automatic trip devices instead of beingarranged as an automatic stop device. These and other modifications ofthe invention which will occur to those skilled in the art, although notspecifically described herein, are within the scope and contemplation ofthe invention.

I claim:

In a quick-setting stop device for a machine tool having a reciprocatorymember to which is connected for parallel movement therewith a barhaving thread teeth formed on one face thereof, the combination of ashell slidable on said bar for longitudinal movement relative thereto, alever having its arms angularly disposed relative to each other at anangle of about and pivoted at the juncture of said arms on an axisparallel to said bar and adjacent but to one side of the thread teeththereon, a worm screw rotatably mounted on the arm of said leverextending adjacent said thread teeth and adapted to engage said teeth,the other arm of said lever extending along the side of said shell, 2.spring acting on said lever and biased normally to press said screwfirmly into threaded engagement with the thread teeth on said bar,whereby said shell may be locked to said bar but may be movedlongitudinally relative thereto by rotation of said screw and pressureon the arm of said lever extending along the side of said shell willswing said screw to disengaged position.

MICHAEL JOSEPH KARR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

